Clogged valves on unused or barely empty cans that leave you no hope of further use – this image has long defined the average day for many craftsmen. The rubber-based components in conventional PUR valves in PUR foam cans, repeatedly lead to blockages that can not be removed, particularly in the case of incorrect storage – once clogged, the can is only fit for the bin.

Seaching for the solution

Together with our long-term partners, we set about developing an alternative to the recognised valve techonology usually found on the market. Our work was aimed at finding a solution that firstly, did not immediately already lead to clogging upon first use and secondly, is compatible with all currently used foam guns. Solid valves are not totally unknown in the market, but up until now were too expensive and inadequate in terms of system compatibility in gun foams. Finding a complete solution that meets all requirements sounds easier than it is in practice: substituting tried and tested materials requires us to explore new directions in every area.

Four years to perfection

Even with our development of valves for gun foams, it took a few years until we found the perfect solution. The pre-selection and decision of individual material components alone takes up a lot of time. The resistance to the most varied chemicals and solvents must be tested in long-term trials in great detail to be able to guarantee serviceability. After the suitable materials were determined, we had to make sure that our clog-free solid valve could also stand up to the different mechanical as well as thermal loads. A question that can only be answered via sufficient filling tests and field tests – tests involving customers and users all over Europe. We gave ourselves 24 months for these investigations in order to get the most precise results and armed with these, to make the necessary modifications to the product. Of course we also then carried out practical investigations on these so that with the TPE Valve PUR-RF 07 today we can present an optimally functioning product in series maturity. TPE stands for “thermoplastic elastomers” – materials that, unlike rubber, are 100% resistant and defend against the negative effects of PUR foam formulations.

Excursus: Thermoplastic Elastomers

Thermoplastic elastomers are materials in wich elastic polymer chains are bound in thermoplastic material. Although unlike with pure elastomers no chemical linkage using a laborious and high-temperature vulcanisation process is necessary, the pieces produced still possess elastic rubber properties thank to their special molecular structure. As plastic waste, they can be melted down again and re-processed. Due to the very short cycles in production resulting from the plastics-related manufacturing process, elastomers are widely implemented in automotive chassis sealants as well as in construction elements.

Perfection thanks to team work

The ever growing complexity in the formulation of PUR foams and the number of different PUR systems make it necessary to bring in the know-how of experts from different areas for perfect product development. That’s why we invested in the early stages of development, amongst others, in the expertise of the Budapest University of Technology and Economics renowned also in Western Europe, which supported us greatly with the selection and the properties of the material components. In this way, we brought a product to the market with our TPE Solid Valve PUR RF 07 that functions optimally, presents a real innovation for the industry and additionally sets new benchmarks.

A product with added value for all

The developed valve offers added value in all sorts of ways. Preventing clogging means the amount of environmentally damaging waste is drastically reduced because the cans can be added to rubbish disposal almost 100% empty. A reduction in the amount of gas loss makes it possible to store the PUR foam cans for significantly longer. Overall, this improvement on gas loss leads to a significant increase in the quality of the product. The logistics costs can also be heavily reduced with the PUR RF 07 as one valve can be used for two systems – adapter foams and gun foams. And all this with the greatest possible compatibility with all PUR foam guns.